Janet Ferl

Intelligent Flexible Materials for Deployable Space Structures (InFlex)

Deployable structures will play a major role in future space exploration missions, as they have in past human exploration. Deployable inflatable structures have been proven to offer high packing efficiency for reduced mass and launch cost, and a highly reliable expandable volume for space systems such as habitats, airlocks, space suits, deployable storage facilities, ballutes, and rover components. ILC Dover and its teammates TIAX and NASA JSC are developing materials & technologies for these structures under a NASA ESR&T within the NASA Exploration program. The goal of this work is to improve system reliability and increase infrastructure flexibility by incorporating intelligence and material improvements in inflatable materials that can be used in a variety of system architectures. Multifunctional modular and scalable materials are being developed that will become the building blocks for many exploration infrastructure needs. An inflatable rover/habitat/airlock will be used as a study reference point for design and demonstration of fully functional prototypes. Inflatable structures typically consist of an inner bladder for gas containment, a structural restraint layer that supports loads and a thermal and micrometeoroid protective layer. Technologies that are being embedded in the inflatable components are as follows: • Enhanced radiation protective materials (various insertion locations) • Self-healing bladder materials • Distributed sensor system for structure health monitoring and system knowledge • Signal transfer system for data and a display & warning system • Localized power generation and storage for distributed sensors & actuators • Low permeation bladder materials • Anti-microbial agents for crew (internal) and planetary (external) protection Numerous technologies and approaches to developing an integrated solution are being explored and trade studies performed to identify the optimal technologies for advancement. Bladder permeation reductions are being made through the inclusion of vermiculite nano- platelets or other nano-materials, metalization, and multi-layer laminates. Structural health monitoring has been demonstrated by radio frequency interrogation of embedded conductive path sensors (conductive fibers or printed/etched traces for breakpoint detection in various layers) that also can be used as signal transfer paths for distributed sensors or power systems. Other health-monitoring technologies that utilize electrical impedance

Dust Mitigation Solutions for Lunar and Mars Surface Systems

Dust mitigation has been identified as a major obstacle to lunar and Mars surface operations for space suits, robotics, and vehicle systems. Experience from the Apollo program has demonstrated that lunar stays of limited duration will be difficult and dangerous if dramatic measures are not taken to mitigate the impacts of dust contamination. Numerous mitigation approaches have been studied in the past including electrostatic materials, cleaning techniques, and suit-locks. Many of these approaches are effective in operation but are challenged by the trend of returning to a single space suit system, similar to Apollo, which is used for launch/entry as well as surface and contingency extra-vehicular activity (EVA) operations. Bringing the surface suit inside the vehicle after surface EVA will transfer surface material in the vehicle. Studies are currently ongoing to identify containment methods of isolating the space suit or robotics elements from the surface dust during EVA operations through the use of removable covers. This approach not only protects the underlying components from dust contamination but also precludes the transfer of dust into the vehicle or habitat. Similar containment analogs are employed everyday throughout the world when using chemical, biological, or radiological protective equipment in the military and various industries. Prototype covers for the space suit have been designed and tested to create robust durable covers that protect the suit from degradation without encumbering mobility, while also being simple to don & doff. Accompanying procedures, such as removing the covers just outside the airlock, will keep the dust off the underlying space suit and therefore prevent it from entering the vehicle. The covers may also include any dust mitigating materials advances such as lotus-effect coatings as they evolve, simplifying certification and lifecycle impacts of the underlying space suit. First order system level trades have been conducted on various technical approaches. Results of the trade studies, discussion of the analogs that are in existence and prototype testing will be presented in the paper.

Trade Study of an Exploration Cooling Garment

A trade study was conducted with a goal to develop relatively high TRL design concepts for an Exploration Cooling Garment (ExCG) that can accommodate larger metabolic loads and maintain physiological limits of the crewmembers health and work efficiency during all phases of exploration missions without hindering mobility. Effective personal cooling through use of an ExCG is critical in achieving safe and efficient missions. Crew thermoregulation not only impacts comfort during suited operations but also directly affects human performance. Since the ExCG is intimately worn and interfaces with comfort items, it is also critical to overall crewmember physical comfort. Both thermal and physical comfort are essential for the long term, continuous wear expected of the ExCG. The subsystems and design considerations that were studied include the amount and placement of cooling, the ventilation system, the carrier structure in terms of the number and configuration of garment components, garment materials, the cooling line configuration, ancillary equipment, water connectors, and a bio-medical harness. The guiding principle of the ExCG system is the physiological design of cooling. Based on this study, it is recommended that the ExCG be configured as a one piece garment with physiologically placed cooling lines on the head, back, top of the shoulders, ribs, lower arms, inner thighs, and calves. Placement of tubing in these physiological zones was based on the results of a cooling analysis and crew survey. An optimal cooling line configuration was selected through analytical and experimental investigation of different materials, tube geometries, and tube routing. An assessment of the ventilation system, beginning with a historical perspective and considering a wide range of options including a vent system on the pressure garment, concluded that a vent system should be integral with the ExCG. Materials were selected based on the mapping of material functionality of different physiological zones. This paper will discuss the recommended ExCG system concept and its expected ability to meet goals and requirements described in the Crew, Robotics, and Vehicle Equipment (CRAVE) delivery order (DO 25) for the ExCG. This concept will maintain crew thermal balance and physical comfort while simplifying ExCG operations and logistics.

Development of a Space Suit Soft Upper Torso Mobility/Sizing Actuation System with Focus on Prototype Development and Manned Testing

ILC Dover Inc. was awarded a three-year NRA grant for the development of innovative spacesuit pressure garment technology that will enable safer, more reliable, and effective human exploration of the space frontier. The research focused on the development of a high performance mobility/sizing actuation system for a spacesuit soft upper torso (SUT) pressure garment. This technology has application in two areas (1) repositioning the scye bearings to improve specific joint motion i.e. hammering (Figure 1), hand over hand translation (Figure 2), etc., and (2) as a suit sizing mechanism to allow easier suit entry and more accurate suit fit with fewer torso sizes than the existing EMU. This research was divided into three phases. In phases 1 and 2 SUT actuation technologies were developed and evaluated. In the final phase, which this paper focuses on, a field of previously selected actuation methods was narrowed to one active, pneumatically driven system, and one passive, cable driven system. These systems were developed into fully functioning prototypes which were outfitted to a table top SUT mock-up which was later integrated into a full suit and tested. Both of these systems were shown to be successful in positioning the SUT shoulder joint interface angles in a designated location and holding there until task completion. The control mechanisms used for both the active and passive system was also modeled and developed. The final phase was concluded by collecting video of a manned demonstration of two of the sizing systems in effect. This paper will summarize the findings of this three year research with emphasis on the details of the final phase.

Space Suit & Protective Equipment Technology for Commercial Launch Entry Applications

ommercial spaceflight is growing rapidly and advancing towards human-rated vehicles to support flights to the International Space Station, and commercial endpoints. Provisions for human safety and performance in nominal and emergency situations will be critical to the creation of a reliable space transportation system. Commercial space companies are considering various approaches to Personal Protective Equipment (PPE) ranging from emergency breathing systems to space suits. Several hood/mask and space suits have been developed recently for application in commercial spaceflight. These suits and masks were designed to leverage commercial PPE technologies, such as chemical protective suits and Portable Air Purification Respirators, to minimize production cost and performance risk, and increase safety. By blending components and technologies from existing space suits, commercial PPE, and emerging technologies, an optimal approach to crew protection can be achieved for each vehicle type. This paper will discuss considerations for developing a commercial PPE system for use in space flight applications including system requirements, aesthetics, design and performance details of recently developed equipment, and what is required to transition this equipment into use on commercial vehicles.

Study and Development of a Radiation Shielding Kit

A critical aspect of space exploration is the probability of exposure to high energy particles from Solar Particle Events (SPE) and Galactic Cosmic Rays (GCR). Radiation shielding will be an enabling feature for exploration architectures that return man to the moon and Mars. A radiation shield that could be attached to different kinds of platforms would ideally serve as a second line of defense for localized protection of astronauts and equipment. It is envisioned that a flexible and lightweight radiation shielding kit would contain elements that could be worn and deployed in various configurations and packed into a manageable volume for flight. LaRC and ILC Dover have undertaken a task to study and develop a flexible radiation shielding kit with state of the art effectiveness in scattering galactic cosmic radiation and solar particle event radiation. Polyethylene, with a high density of hydrogen in its molecular chains, shows the greatest potential for radiation protection. A material ply-up has been developed that provides 1.0 g/cm2 of shielding while maintaining manufacturability and acceptable functionality in terms of stowability, flexibility, and ease of use. Concept generation and system trade studies resulted in selection of vest and blanket architectures that best meet the radiation shield kit requirements developed by LaRC. In addition reconfigurable stowage containers have been developed using a 0.5 – 1.0 g/cm2 ply-up. Prototype components and test sample ply-ups have been fabricated proving the feasibility of flexible, reconfigurable components and providing a key testbed for evaluation and future development. Radiation testing and material analysis show shielding effectiveness and acceptability for use in a vehicle or habitat. This paper will discuss the results of the radiation shielding kit study and offer recommendations for further study.

Trade Study of an Interface for a Removable/Replaceable Thermal Micrometeoroid Garment

Effective thermal and micrometeoroid protection as afforded by the Thermal Micrometeoroid Garment (TMG) is critical in achieving safe and efficient missions. It is also critical that the TMG does not increase torque or decreased range of motion which can cause crewmember discomfort, fatigue, and reduced efficiency. For future exploration missions, removable and replaceable TMGs will allow the use of different pressure garment protective covers and TMG configurations for launch, re-entry, 0-G Extra Vehicular Activity (EVA), and lunar surface EVA. A study was conducted with the goal of developing high Technology Readiness Level (TRL), scalable, interface design concepts for TMG systems. The affects of TMG segmentation on mobility and donning were assessed. Closure mechanisms were investigated and tested to determine their operability after exposure to lunar dust. A TMG configuration with the optimum number of segments and location of interfaces was selected for the Mark III spacesuit. Interface segments were designed based on the study of closure mechanisms, dust test results, and trade studies of interface concepts. Interface segments were fabricated and tested to verify meeting the goals and requirements described in the Crew, Robotics, and Vehicle Equipment (CRAVE) Delivery Order (DO), DOCRAVE-EC5-D026. The most important criteria driving the interface design were determined to be the ability to don the TMG over a pressurized suit, the ability to actuate interfaces with a pressurized gloved hand, limiting the negative affect on mobility, and interface weight. The principal design concept of attaching the TMG by cinching it around the pressure garment hardware has been pursued by fabrication of an arm TMG segment for the waist entry I-Suit and D-Suit spacesuits. Results of the trade study and prototype evaluation are presented in this paper.